What Is Ipamorelin?
Ipamorelin is a five-amino-acid synthetic peptide that tells your pituitary gland to release growth hormone — and it does it more selectively than almost anything else in its class. That selectivity is the whole point. Older growth hormone secretagogues like GHRP-6 and GHRP-2 work, but they also drag cortisol and prolactin up with them. Ipamorelin doesn't. You get the GH pulse without the hormonal noise.
It was developed in the late 1990s by Novo Nordisk and studied in human volunteers as early as 1999.[1] The pharmacokinetic data from those early trials confirmed what animal studies suggested: ipamorelin produces a sharp, dose-dependent GH spike with a relatively clean side effect profile.[1] That profile is why it became one of the more widely used peptides in hormone optimization clinics over the past decade.
It's not FDA approved. It's used in the US primarily as a research compound, and in some clinical settings through compounding pharmacies. If you're considering it, that regulatory reality matters — and it's covered in detail below.
Ipamorelin is a selective GH secretagogue that stimulates pulsatile growth hormone release without significantly raising cortisol or prolactin — a key advantage over older peptides in its class.